1. Field of the Invention
The present invention relates to a method and apparatus for introducing a particulate or pulverulent material into a flow of gas confined within a tube or duct for pneumatically transporting said material by said gas flow. The said material may be introduced into the gas flow exclusively in order to have the material transported by that flow. However, normally it is also intended to obtain some kind of treatment of the particulate or pulverulent material during said transport. Thus, for example the material may be flash dried in the transporting gas flow which may consist of hot gas or air, or some other kind of physical or chemical interaction between the material and the gas may take place during the transport of the material.
2. Description of the Prior Art
From Applicants' Danish published patent specification No. 129.602 it is known to flash dry sand or a similar particulate material in a transporting flow of drying gas, the material being thrown into said flow of drying gas by means of a rotor. In order to obtain the best possible surface contact between the particulate material and the drying gas and in order to obtain a good suspension or "airbearing" of the material in the transporting and/or treating gas it is important to obtain a good spreading of the particles in the material before or when these particles are introduced into the transport tube or duct. By using a throw-in rotor or other suitable mechanical throw-in devices it is possible to obtain an acceptable spreading of the particles of the material provided that the stream of the material generated by the throw-in device is relatively small. This condition, however, does not really harmonize with the fact that it is normally desired to have the greatest possible amount of material treated and/or transported in the smallest possible period of time.